I have an Intel ac-8265 intalled in a Dell XPS15 9560. Everything is fine, unless I am on specific wireless networks on 2.4GHz. The moment I turn on my Logitech MX Master bluetooth mouse, the internet disconnects, or is extremely poor. The moment I turn the mouse off, it is back to normal. Any chance to fix this on a firmware-level?
Yes, it does matter. You need to consult with dell for compatibility.
Nicely put Mr Hill, I have none of these compatibility or regulatory issues. The device works, and is officially supported by Dell for my device:
The issue is obviously physical interference on YOUR hardware. Thought it might be useful for troubleshooting but I was mistaken... Let me know if you want to troubleshoot seriously.
Bluetooth uses the same 2.4GHz frequency band that is used by WiFi. Further, within a single machine, the same transmitter and receiver are used to support both WiFi and Bluetooth communication. Bottom line, you aren't saying anything that would signal to me that there is anything wrong. This is normal. Switch your WiFi to use the 5GHz band. This can additionally speed up WiFi communication by a factor of 3x (or more, with appropriate Router) over what is possible using only the 2.4GHz band (even if Bluetooth wasn't stealing bandwidth).
[Aside: Just to be complete, USB 3.x also uses 2.4GHz signalling on its cables and all it takes is one cheap/bad USB cable (which can act like an antenna) and it too will interfere with WiFi.]